Objective evaluation of various extracardiac factors of cerebral origin in extrasystole]

Partial integral rheography was used to study the volume velocity of brain blood supply (BBS) in 39 flying operators aged 20-39 years during continuously increasing bicycle ergometer testing. In good exercise tolerance, the dynamics of cerebral blood flow was found to be biphasic: 1) a rapid increase in BBS volume velocity at the first stages of exercise and 2) its subsequent stabilization. Stabilization of cerebral blood flow at 25% levels of blood minute volume was achieved by tonic tension autoregulation of the intracerebral arteries and adequate venous return. During the bicycle ergometer testing, the examinees with transient premature contractions showed impaired autoregulation, i.e. a considerable decrease in regional artery tone, cerebrovascular hyperperfusion and circulatory disorder resulting in the ++cerebro-cardiac syndrome with extracardiac premature beats. With drug therapy of extracardiac premature contractions, the tone of cerebral arteries and the level of intracranial hemodynamics should be borne in mind and corrected.